I have been playing around with custom brushes which are great. One thing I notice is if you import a custom brush that has areas of semi transparency Verve makes it a solid shape (first image) brush plus mark in Verve

You can achieve a sort of semi transparency by bringing down the visibility but some of the brush shape disappears.Second image

I bring this up not as a criticism but as a jumping off point for custom brushes. Semi transparency in custom brushes would allow for a more convincing interaction with the canvas rather than appearing to sit on top of the canvas as a shape.